MORTGAGE SERVICING RIGHTS - Changes in mortgage servicing rights (Details) - Changes in mortgage servicing rights - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2017		Dec. 31, 2016	Dec. 31, 2015
Mortgage Servicing Rights
Balance, beginning of period		$ 339		$ 486	$ 694
Originated		63		95	148
Amortization		(169)	[1]	(242)	(356)	[1]
Balance, end of period		233		339	486
Valuation Allowance
Balance, beginning of period		(23)		(3)
Decrease (increase) in impairment reserve	[1]	23		(20)	(3)
Balance, end of period				(23)	(3)
Mortgage servicing rights, net		$ 233		$ 316	$ 483

[1] (1) Amortization expense and changes in the impairment reserve are recorded in mortgage servicing, net.